Two hundred thousand years ago, our ancestors lived on the African savanna. And they were very good at being scared of dangerous stuff.

If you weren't scared of snakes, you got bitten by a snake and you died. Your genes didn't get passed on.

If you weren't scared of not belonging to the tribe, you got evicted. And you died. Your genes didn't get passed on either.

So we evolved to be scared of stuff that was dangerous.